2 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 63, 



29." The bones were met with in a peat swamp which forms a part 

 of the overburden of the iron ore. This peat, about 6 or 8 feet deep, 

 was being removed by hydraulic operations and thus the bones 

 were exposed. They were at or near the bottom of tlie peat. 



This discovery brings to us new information regarding the time 

 of disappearance of Bison occidentalis. From the remains of this 

 species hitherto discovered, the writer had concluded that it had died 

 out before the oncoming of the Wisconsin ice sheet. Mr. Uliler 

 reports that underneath the peat of the bog where the bones were 

 found there is about 30 feet of drift. On my consulting Prof. Frank 

 Leverett about the age of this drift, he wrote as follows : 



The drift at the iron mine in section 19, towii^hip 46, range 29, near Crosby, 

 Minnesota, is a moraine of red Wisconsin drift, of about the age of the Kala- 

 mazoo morainic system in Michigan, and the onter moraine of tlie Green Bay 

 lobe in Wisconsin. It is older than the gray drift of Minnesota and younger 

 than the Shelbyville, Bloomington, and Marseilles moraines of Illinois. It is, 

 therefore, about mid- Wisconsin in age. 



We can be certain therefore that Bison occidentalis lived in Min- 

 nesota until the middle of the last glacial stage. How much longer 

 we can not now determine. Nor can we be certain just when the 

 bones of Bison bison were left in that peat swamp. The two species 

 may have lived in that region together, or the existing buffalo may 

 have arrived there after the other species had become extinct. 



It will perhaps occur to those reading this account that these 

 animals became mired in that bog and perished. Possibly some of 

 them did thus meet their fate ; but others may have died there from 

 other causes. It may be doubted further that more individuals died 

 in that bog than died on an equal area of upland. In the bog, where 

 water was always present, the bones were preserved; on the hills, 

 they gradually dissolved into soil. 



In studying the skulls the writer has taken a series of measure- 

 ments in order to show the dimensions of the parts. See Table 1, 

 page 3. In the first and second columns are measurements taken 

 from the two complete skulls of B. occidentalis; in the third, fourth, 

 and fifth columns are measurements from the injured skulls. In 

 the sixth column are corresponding measurements of a good speci- 

 men of the existing bison (Cat. No. 22, 374, U. S. N. M.). In the 

 seventh are similar measurements of a specimen of the European 

 bison, Bison honasvs (Cat. No. 11, 514 U. S. N. M.). In an eighth 

 column are measurements derived from a very complete skull of 

 Bison alleni found in Alaska (Cat. No. 7706 U. S. N. M.). This 

 specimen was described by the writer in 1913.^ 



1 Proc. U. S. Nat. Miis., vol. 46, pp. 182-192, pis. 16, 17, test figs. 7-9. 



